BERLIN — When the German Parliament set aside its objections and voted on Wednesday to approve a bailout for Greece, the chief proponent was both an architect of the deal and one of those raising fundamental questions about it: Germany’s finance minister, Wolfgang Schäuble.

Mr. Schäuble, who as much as anyone is the face of the austerity policies imposed by Germany on poorer European nations, had suggested just weeks ago that Greece might be better off going its own way rather than acceding to the bailout terms to remain in the euro.

Yet he had also helped, against long odds, to conclude that deal, eventually worth up to 86 billion euros, or $95 billion, that will unlock money necessary to allow Greece to stay current on its debts while imposing sweeping changes on its economy and finances. Those tensions — between his role as enforcer of the German values of frugality and order on one hand and Germany’s role holding Europe together on the other — reflect the deep strains within Germany about how to maintain its own values while also taking on leadership of a fractious and sometimes hostile continent.

Like his boss, Chancellor Angela Merkel, Mr. Schäuble has proved adept at navigating between those roles, simultaneously reassuring his fellow conservatives that he is guarding against giveaways to the Greeks while retaining credibility outside Germany as a proponent of European unity and integration.

Addressing Parliament on Wednesday as it considered the third bailout for Greece since 2010, he acknowledged doubts but said that this time the government in Athens was serious about enacting economic reforms and that it was thus worth offering further assistance and proving that Europe could stick together.

“Of course, after the experience of the past months and years, there is no guarantee that everything will work, and doubts are always allowed,” he said. “But in view of the fact that the Greek Parliament has already passed a large part of the measures, it would be irresponsible not to use the opportunity now for a new start in Greece.”

Political tension before the vote on Wednesday, in which conservative lawmakers staged a revolt against extending more credit for Greece, revealed the deep internal divisions being felt in Germany over its dual role.

In the end, 63 conservatives voted against, three abstained and 17 simply did not show on Wednesday. In July, there were 60 against and five abstentions — one of the biggest blows to Ms. Merkel during her nearly 10 years in office.

But the measure ultimately passed by a substantial margin, 453 to 113.

Leading the way was Mr. Schäuble, who at 72 is Parliament’s longest-serving deputy and has held virtually every top post in Germany, save that of chancellor.

“A big chunk of the German public believes he has their concerns in mind, that when he conducts negotiations he works for Germany, so that it is not cheated on,” said Harald Schoen, a professor of politics at Mannheim University.

Ms. Merkel, who is nothing if not pragmatic, likely had all this in mind when she ceded the parliamentary leadership role to Mr. Schäuble on Wednesday.

In any case, the 25-year-old dance between Ms. Merkel and Mr. Schäuble remains a complex political relationship, and interpreting it is one of Berlin’s most popular parlor games. While some senior officials speak of a deep rift, another official familiar with both politicians insisted: “There is a deal. She gives him space, freedom to act. And he is loyal.” But few people truly know.

Both politicians were protégés of former Chancellor Helmut Kohl. After Mr. Kohl lost power in 1998 and then, tarnished by a party finance scandal, stepped down as leader of his Christian Democrats, it was Ms. Merkel who bested Mr. Schäuble in the ensuing power struggle.

“His relationship with Ms. Merkel is not completely unburdened by the past, but overall, he enjoys a great deal of respect, and that is why working with Mr. Schäuble helps her,” said Uwe Jun, a professor in politics at the University of Trier.

Video

Schäuble Urges Yes Vote on Greece Plan

The German finance minister Wolfgang Schäuble told Germany’s Parliament that approving the Greek bailout proposal would give Greece a chance at a new start, but with “no guarantee” it would work.

By REUTERS on Publish Date August 19, 2015.
Photo by Wolfgang Kumm/European Pressphoto Agency.
Watch in Times Video »

The finance minister, a lawyer, is a man of such strong will that he was back at work months after an assassination attempt in 1990 left him unable to walk and having to use a wheelchair.

Germans see in him a disciplined, smart negotiator; polling shows that 40 percent to 50 percent of avowed supporters of the far-left Left party admire Mr. Schäuble, said Michael Kunert, of Infratest/dimap, one of Germany’s foremost pollsters. “This is really crazy,” he said.

“He is the uncomfortable figure who speaks the difficult truth, and thus makes the overall result better,” said Detlef Seif, one of the conservative lawmakers who nonetheless voted against the Greek deal on Wednesday.

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That image starkly contrasts with one held in southern Europe and beyond, where he has been lampooned as the ugly German — daubed with a swastika on the cover of Greek magazines.

Mr. Schäuble, who in public has shrugged off the cartoons, is in fact probably the most pro-European figure in Germany’s government. He belongs to a generation that remembers how the United States and Europe helped Germany to recover after 1945, to accumulate wealth and — through the European Union — play a prominent role in the Continent’s affairs. He hails from the very southwest of Germany, near the border with France.

“The French ministers, the government,” said Barbara Kunz, a research fellow on French-German relations at the French Institute for International Relations, “know he is a Francophile and is fluent in French. He embodies the French-German couple almost naturally, or at least more naturally than Merkel, who has less ties with France.”

She added: “Schäuble embodies this old, western Germany, Bonn’s Germany.”

Despite their different backgrounds, Mr. Schäuble and Ms. Merkel, 61, who grew up in the Communist East, work closely together.

In the all-night negotiations to save the euro in July, Ms. Merkel met repeatedly with President François Hollande; Donald Tusk, the president of the European Council; and Alexis Tsipras, the Greek prime minister. Mr. Schäuble was not present, but, as both politicians confirmed this week, he was in constant touch.

Before Wednesday’s vote, the two made no public appearances together. But first Ms. Merkel and then Mr. Schäuble granted 20-minute interviews to German television, each following Ms. Merkel’s maxim from July — to “look ahead.”

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A version of this article appears in print on August 20, 2015, on Page A9 of the New York edition with the headline: A German Navigates Dual Roles in Greek Bailout . Order Reprints|Today's Paper|Subscribe